# Relationship history for MSHA mine 1517312

Current hierarchy: **CRH PLC → Mountain Materials Inc. → Grassy Stone**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Rick  Ruth → Grassy Stone; 1978-03-09 to 2001-06-30; source msha-controller-operator-history
- **operator_operates_mine:** Ken-Mor Stone Inc → Grassy Stone; 1992-10-01 to 2001-06-30; source msha-controller-operator-history
- **controller_controls_operator:** Rick  Ruth → Ken-Mor Stone Inc; 1992-10-01 to 2001-06-30; source msha-controller-operator-history
- **operator_operates_mine:** Grassy Stone LLC → Grassy Stone; 2001-07-01 to 2006-01-22; source msha-controller-operator-history
- **controller_controls_mine:** Steve L  Lawson et al → Grassy Stone; 2001-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Steve L  Lawson et al → Grassy Stone LLC; 2001-07-01 to 2006-01-22; source msha-controller-operator-history
- **operator_operates_mine:** Mountain Materials Inc. → Grassy Stone; 2006-01-23 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → Grassy Stone; 2006-01-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Mountain Materials Inc.; 2006-01-23 to current/open; source msha-controller-operator-history